Pascal’s superstitions

Posted on November 29, 2008


Joanna Bryson, a colleague of mine from the KLI, has spotted another useful article on superstitions as the by-product of trying to spot useful connections in the environment. The article’s title is “The evolution of superstitious and superstition-like behaviour” and was written by Kevin R. Foster and Hanna Kokko:

Superstitious behaviours, which arise through the incorrect assignment of cause and effect, receive considerable attention in psychology and popular culture. Perhaps owing to their seeming irrationality, however, they receive little attention in evolutionary biology. Here we develop a simple model to define the condition under which natural selection will favour assigning causality between two events. This leads to an intuitive inequality-akin to an amalgam of Hamilton’s rule and Pascal’s wager–that shows that natural selection can favour strategies that lead to frequent errors in assessment as long as the occasional correct response carries a large fitness benefit. It follows that incorrect responses are the most common when the probability that two events are really associated is low to moderate: very strong associations are rarely incorrect, while natural selection will rarely favour making very weak associations. Extending the model to include multiple events identifies conditions under which natural selection can favour associating events that are never causally related. Specifically, limitations on assigning causal probabilities to pairs of events can favour strategies that lump non-causal associations with causal ones. We conclude that behaviours which are, or appear, superstitious are an inevitable feature of adaptive behaviour in all organisms, including ourselves.

From the abstract, it is clear that Foster and Kokko are pursuing the ‘superstitions makes sense given weak but very useful correlations’ approach that a number of other writers have pursued prior to them. The bibliography suggests they are only aware of a fraction of such approach but take the approach in some interesting directions. I’ll most probably use the article when I prepare the final version of the chapter in which I discuss Skinner and his descendants.